The present invention relates to a shock detecting device, and in particular, to a shock detecting device for igniting an ignition element without using electric power.
A shock detecting device is used as a sensor which is set to initiate an anti-shock safety device such as an air bag or a seat-belt tensioner. The conventional shock detecting device is disclosed, for example, in Japanese Patent Laid-open Print No. 249744/ 2nd year of Heisei (1990) which was published in 1990 without examination. In the conventional device, a weight is set to be rotated upon receipt of a shock whose magnitude is above a set value. Due to the resultant rotation of the weight, a firing lever is released from a cam portion of the weight which is biased by a spring, thereby rotating the firing lever. Thus, a firing pin formed integrally with the firing lever is extended outside a housing through a hole formed in a wall of the housing which is perpendicular to the direction of the application of the shock so that an ignition element such as a percussion element is struck.
However, in the foregoing structure, since the firing pin is set to be extended in the opposite direction of the shock, the rotation of the firing lever is too small; and the biasing force of the spring is not effectively transformed into kinetic energy of the firing pin.